An inverter device may convert direct-current electrical power into alternating current electrical power. An inverter may be uni-directional, converting direct current (DC) power from a source to alternating current (AC) power out, or bi-directional, converting DC power from a source to AC power out as well as converting AC power from a source to DC power out to a load or storage device.
A grid-tie or grid-tied inverter is an inverter that is specifically designed to have the AC portion of the inverter connected to the power grid. A grid-tied inverter may be designed to operate within a window of operation for the utility voltage. A grid-tied inverter may be uni-directional or bi-directional. A uni-directional inverter may be used to convert a direct current input from a source, like a solar array, fuel cell or battery, to alternating current at the appropriate frequency and voltage to be received by the power grid. A bi-directional inverter may be used to convert alternating current from the power grid to a direct current to be received by a DC load or an energy storage device, such as an electrochemical element like a fuel cell or battery or an electromagnetic storage element, such as an ultracapacitor.
A ground fault occurs when a current carrying electrical path in a circuit comes into electrical contact with a ground path. The ground path may be a wire (e.g., ground wire) or a portion of a grounded part of an appliance or device. Example grounded parts may include a chassis or frame of the appliance or device.
Ground faults may occur in a variety of scenarios. Damage to the appliance or device may result in the ground fault. In other examples, a human or animal may become the electrical path between the current carrying path and the grounded parts.
The response time in the detection of a ground fault and isolating the ground fault from additional electrical current is vital in preventing damage. Especially in the case of a ground fault caused by a human or animal, the risk of electrical shock is reduced when the ground fault is quickly detected and/or current is prevented from traveling to the ground fault.